Cereal grains provide an extremely important source of nourishment to people throughout the world. For example, in many countries in central Asia, the Middle East, and Northern Africa between 40 and 60 percent of all daily calories consumed by humans are from wheat. The United Nations has suggested that world wide cereal grain production needs to double within the next 50 years in order to sustain current human population growth projections. Accordingly, finding ways to enhance cereal grain production are extremely important in today's society. Numerous studies and publications also suggest the increased need for cereal grain production through out the world in the upcoming future.
The domestication of barley and of emmer and einkorn, both primitive wheats, occurred in northern Mesopotamia to include modern day northern Iraq, Syria and the Anatolian Plain of Turkey over the period of 9000 BC to 4500 BC. The cultural practice of that period was to hand scatter seed over a tilled field. The consequence of this hand broadcasting was to cause kernels to fall as separate seeds resulting in the wheat and barley plants competing in the field environments as individuals. Accordingly, seeds with the best genetic attributes for growth as individuals, as opposed to colony growth, emerged with reproductive advantages. Being more productive they were more likely to undergo natural hybridization with plants displaying similar advantages. Currently modern drills typically place single cereal seeds within a row at a spacing of about one kernel per inch. As was the case in the Neolithic Period, today's commercial fields typically grow cereal crops as individual plants.
As developed throughout history, conventional seeding practices for wheat and barley in the United States are to more or less evenly distribute seeds along a drill row or to scatter the seeds and then cover them through tillage. The volume of seed distributed along the row and the spacing of the rows vary by environment, variety and custom. Seeding rates vary from as low as 50 pounds of seed sown per acre to 150 pounds of seed sown per acre. Row spacing varies from 3 to 12 inches apart, depending on environment, variety and custom. In Georgia it is recommended “That each linear foot of row should contain 20-25 (wheat) seeds.” In Kansas it is recommended that in the field wheat populations range from 600,000 to 1,080,000 plants per acre. In Idaho barley is normally seeded in rows. Occasionally barley is broadcast seeded using a fertilizer spreader followed by a tillage practice that covers the seed.
An alternative seeding method, which is not commercially practiced to any significant degree, is to plant hill plots. Hill plot culture involves planting multiple seeds in the same seed bed or hold or hill causing the crop to grow as a colony of plants in the field environment as opposed to the conventional practice of planting seeds singly so plants grow as individuals in the field environment.
In 1947 Bonnett and Dever proposed using hill plots to eliminate off-types in varietal purification programs and for selecting for disease resistant genotypes. Various researchers have used hill plots as a means of evaluating yield potential of newly selected experimental lines. A likely problem with this method is that the researchers have not used plants selected for attributes for increased yield when grown as a colony of plants. In use, some authors have reported that hill plots were of questionable value for yield evaluation. The major concern voiced by these authors was the greater yield variability in hill plots than was measured in rod row plots. Other authors found hill plots to be useful in yield evaluations, particularly when large populations were being tested and where seed volume of the lines to be tested was limited. Other authors were ambivalent as to the value of hill plots in yield evaluation. Although researchers have used hill plot planting methods for a variety of purposes, it is not known to recurrently select for plants that have superior growth attributes when grown as a colony of plants in a hill plot system and to utilize those plants in the system. Accordingly, previous planting methods and research have not utilized plants genetically selected for their improved colony growth attributes and subsequently used these plants for enhanced commercial yield of cereal grains.
In performing experiments regarding planting methods and genetically selecting plants for their growth characteristics, we have found that it appears there are at least two different gene pools in cereals for enhanced yield. One gene pool promotes yields when plants compete individually in the field environment. Because of extensive plant breeding efforts by numerous public and private cereal breeding programs, the genes in this yield enhancing pool have been extensively mined. A second gene pool promotes yields when plants compete as a colony or collective in the field environment. This second pool of yield enhancing genes has apparently not to date been extensively mined.
Accordingly, an object of the current invention is to select for and exploit plants exhibiting superior colony growth attributes in order to increase commercial yield in cereal grains.